1. Field of the Invention
This invention relates to image processing devices for drawing pictures and images on computer screens in association with sprites and rendering in image processing.
This application claims priority on Japanese Patent Application No. 2003-23444 and Japanese Patent Application No. 2003-23445, the contents of which are incorporated herein by reference.
2. Description of the Related Art
Conventionally, graphical displays using sprites have been frequently used in playing video games and television games as well as other games such as ‘pachinko’ (a Japanese form of pinball). FIG. 7 is a block diagram showing the overall constitution of an image display device using sprites in image processing, wherein reference numeral 1 designates a central processing unit (CPU), 2 designates an image processing device, 3 designates a pattern read-only memory (ROM) for storing compressed patterns of sprites, and 4 designates a display such as a liquid crystal display. Upon reception of instructions from the CPU 1, the image processing device 2 reads sprite patterns from the pattern ROM 3 so as to decode (e.g., expand) the read sprite patterns, which are thus restored to ‘original’ sprite patterns before compression and are expanded in a sprite buffer (not shown) internally arranged therein. The ‘decoded’ sprite patterns are read from the sprite buffer and are then subjected to rendering processes such as magnification (or enlargement), reduction, rotation, and deformation, so that they are drawn in a frame buffer arranged internally of the image processing device 2. Thereafter, the ‘drawn’ pattern data are read out in synchronization with horizontal and vertical scanning timings and are output to the display 4. Conventionally-known technologies regarding the aforementioned display processing using sprites are disclosed in various documents such as Japanese Patent Application Publication No. 2002-16810, Japanese Patent Application Publication No. 2002-112263, and Japanese Patent Application Publication No. 2002-341859.
The conventionally-known image processing device is designed to perform a process for expanding a sprite pattern in the sprite buffer and a rendering process regarding the expanded sprite pattern, thus actualizing synchronization on drawing of an image at a prescribed location of the frame buffer. For this reason, one of these processes whose processing speed is relatively low may cause a bottleneck in image processing; and this reduces a drawing ability in processing.